We started with a box of brownie mix and turned it into a halloween graveyard scene complete with cookie headstones, marshmallow ghosts, and graham cracker coffins lit from below using glowsticks.
This was pretty quick to make, and you could easily modify our design to fit whatever ingredients you have on-hand.
We made ours for a halloween party and had to cut it up ourselves so people would stop taking pictures and start eating it. :-)
Step 1: Layout the graveyard
Make some cookie "headstones". We used a serrated knife saw through some Pepperidge Farm Milano cookies, but anything that is roughly headstone-shaped should work. Make sure the cookies you use are smooth on at least one side so you can write on it frosting later. Do not push the headstones into the dirt yet, we'll do that at the end after applying the green frosting "grass".
Break some graham crackers into small rectangular "coffin lids" and place several of them to mark the "graves" we'll dig up in the next step. Try to keep the breaks clean, since these will be visible at the end. Keep at least one empty grave between each graham cracker "coffin lid" unless your brownie "dirt" is really hard/strong.
We decided that two rows of five graves looked right in our dish given the size of the headstones and coffins we had, but using a different (reasonable) layout probably wouldn't cause any problems.